1. Field of the Invention
The present invention relates to a colored golf ball having a fluorescent color. More specifically, the invention relates to a colored golf ball endowed with an excellent spin performance and durability, an appearance characterized by outstanding visibility, stylishness and luxury, and an excellent weather resistance.
2. Prior Art
Lately, not all golf balls are white; a variety of colored balls have appeared on the market in response to the preferences of golfers. In particular, highly stylish colored golf balls and colored golf balls endowed with a luxury have been developed to suit the tastes of women golfers.
At the same time, with the increasing versatility of golf balls in recent years, adopting a ball construction of at least three pieces—namely, a core, an intermediate layer and a cover—is becoming a precondition for the creation of golf balls acceptable to the skilled golfer. In multi-piece solid golf balls composed of three or more pieces, the sensory impression elicited by the ball varies with differences in the thicknesses and colors of the respective layers. Moreover, in addition to ball performance, from a psychological standpoint, using a golf ball having a favorite color imparts a beneficial psychological effect on the golfer, improving performance by the golfer. Yet, few colored golf balls for the skilled golfer which take such factors into account, particularly colored golf balls with an outermost cover layer made of a polyurethane material, are available on the market.
JP-A 10-155937 discloses a golf ball colored in shades other than white. Expressing the color tone of this ball in the Lab color system, the cover is given a blue, green, pink, yellow or orange color having an L value of at least 80, an a value of from −30 to +30, and a b value of from −30 to +30. Although this golf ball is more stylish than earlier colored golf balls, the colors within these ranges are pale colors, as a result of which the ball lacks a bright coloration and a high-quality feel. There is also room for improvement in achieving further stylishness.
JP-A 2000-024139 describes a golf ball in which the cover-forming material includes from 3.0 to 7.0 parts by weight of one or more type of fluorescent pigment and from 0.05 to 0.5 part by weight of titanium oxide per 100 parts by weight of resin, and which has one or more coat of clear paint on the cover. However, given that the amount of fluorescent pigment included is somewhat high and that from 0.05 to 0.5 part by weight of titanium oxide is additionally combined therewith, the color tends to be too intense, in addition to which the ball is somewhat lacking in luminosity. As a result, although this prior-art ball does have an excellent visibility, it falls a bit short in terms of the luxury.
JP-A 2000-254250 teaches a brightly colored golf ball of good visibility which has at least one colored layer containing a white organic pigment and/or white inorganic pigment, a fluorescent pigment, and an inorganic pigment and/or organic pigment. However, this golf ball has a pale color tone, and thus leaves something to be desired in terms of the luxury and brightness of color.
JP-A 2003-126299 discloses a golf ball of a bright yellow color which, even under harsh usage conditions, is not readily subject to fading or discoloration and has an excellent weather resistance. This golf ball, although brightly colored and having an excellent weather resistance, exhibits a rather deep yellow color which, unfortunately, is a color tone that falls short in terms of the luxury.
JP-2004-081350 describes a painted golf ball in which a coat of paint containing a polarizing pigment has been formed on the surface of a golf ball body. The paint also contains a non-white colorant. The surface of the golf ball body is imparted with a color other than white, and has a lightness L* value, based on the L*a*b* color system, of 50 or less. However, this golf ball does not have a sufficient lightness, and falls somewhat short in terms of stylishness and visibility.
JP-A 2004-033594 discloses a golf ball which is colored blue, pink or yellow, and which has an excellent visibility without being visually disconcerting. The L, a and b values are described as satisfying a specific formula. Even though this golf ball does indeed have an excellent visibility without being visually disconcerting, there remains room for improvement in such attributes as the brightness and luxury.
JP-A 2007-144097 describes a golf ball of enhanced visibility wherein the cover is formed of a cover material composed of a transparent resin composition to which has been added a fluorescent dye. Although this golf ball does indeed achieve a relatively vivid color tone, when a fluorescent dye is used, color changes such as fading tend to arise with the passage of time and exposure to the weather. Accordingly, here too, there remains room for further improvement.